Gray's young-DiCaprio looks and his small stature earn him plenty of grief in the A's clubhouse, but Gray's teammates are firm believers in his talent. And with Jarrod Parker out for the season after Tommy John surgery, the A's turn to Gray as their Opening Night starter on Monday against the Indians.

"He's the guy you want with the ball in his hand," catcher Stephen Vogt said last week. "Sonny is fearless. He has the ability to be an ace on any team in baseball right now."

He's listed at 5-foot-11, but is a good inch or two shorter than that, so Gray reminds many people of former Astros star Roy Oswalt. He has also drawn comparisons to a former A's starter, Tim Hudson, a smaller-stature right-hander who burst onto the scene in 1999. Like Gray, Hudson was an Oakland draft pick out of a Southern college program, Hudson from Auburn and Gray from Vanderbilt.

Hudson has seen Gray on TV, and he also watched him when Gray faced the Giants this spring.

"I can see it," Hudson said of the similarities between the two. "He's not a very tall guy and he's got good stuff - he throws a lot harder than I did, but I think our presence on the field is similar. I think there's something built in when you're constantly having to prove yourself.

"You can tell he has confidence. It's not an overwhelming swagger, but a quiet confidence - 'I'm going to show you. I might not look like a whole lot, but you're going to find out what I've got.' "

Then there is the stuff, including a four-seam fastball that registers in the mid-90s, and a superb curveball. Gray spent the spring working on his changeup and his two-seamer, and he also has a slider he'll use on occasion.

One scout who saw most of Gray's spring starts and several of his 12 regular-season appearances last year said that the rest of the league "is in trouble," though he used more colorful language. When the A's face his team, the scout said, he hopes Gray gets stuck in traffic.

"He's got a 96 mph fastball that moves - and it's a challenge to catch," Jaso said. "Therefore, he's not that fun to hit. With him, it's just getting strike one, because the ball moves so much, and he can take (velocity) off and get more movement or he can amp up and blow it by you for a strikeout.

"He's got a good sense of what he's capable of, and he's developing in the right direction."

Gray, 24, was drafted in 2011. Jaso said that considering that, he's well ahead of schedule.

"Usually, three years into pro ball, pitchers have no clue," Jaso said. "Sonny does. He's strong mentally, and that gives him a big advantage."

"Sonny is pitching like he's been here for five years," right fielder Josh Reddick said. "He's a bulldog. I'm sure he didn't picture being the Opening Day starter in his first full season, but he is, and he'll be fine. He goes out there with an 'I'm better than you' attitude - and then he shows he is better than anyone else."

Rain is in the forecast for Opening Night, but when asked about the weather for his start, Gray flashed that smile and said, "It'll be Sonny."